Blade with internal rib having corrugated surface(s)

ABSTRACT

A blade includes an airfoil body defined by a concave pressure side outer wall and a convex suction side outer wall that connect along leading and trailing edges and, therebetween, form a radially extending chamber for receiving the flow of a coolant, the airfoil body having an outer surface and an inner surface facing the radially extending chamber. A first corrugated surface is on at least a portion of the outer surface of the airfoil body; and a first rib partitions the radially extending chamber, the first rib including a first side and an opposing second side. A second corrugated surface is on at least a portion of at least one of the first and second sides of the first rib.

BACKGROUND OF THE INVENTION

The disclosure relates generally to turbomachine blades, and moreparticularly, to a blade having corrugated outer surface(s) to assistwake mixing and an internal rib having a corrugated surface to assist incooling.

Turbomachine blades include airfoils that accelerate flow throughcontraction of area and the introduction of tangential velocity. Therelative flow velocity exiting, for example, a gas turbine airfoil isquite high, typically with Mach numbers of 0.5 or higher. The finitethickness of an airfoil trailing edge, however, creates a velocitydeficit, i.e., a wake, which introduces losses in the flow throughviscous mixing. FIG. 1 shows an example of a typical unsteady lossprocess for a turbine blade row 10 operating behind a turbine vane row12. At location 14, a wake is generated by a finite trailing edgethickness of the airfoil of vane row 12, resulting in aerodynamic lossesdue to mixing of the wake with the mainstream. At location 16, the wakeinteracts with potential field of a downstream airfoil of blade row 10,and it begins to distort. At location 18, the wake is segregated intodiscrete packages by the leading edge of airfoils in blade row 10. Atlocation 20, a pressure gradient in the airfoil passage (between bladesof blade row 10) causes wake packets to stretch and migrate, causingaerodynamic losses due to mixing of the wake packets (referred to as“free stream mixing”). That is, when the wake is ingested into adownstream airfoil of blade row 10, the wake undergoes a stretching anddilation process that exacerbates the losses associated with the mixing.At location 22, the wake packets interact with the boundary layer of theblades in blade row 10 downstream of the airfoils' wake, causing higheraerodynamic losses (airfoil surface losses). Unsteady loss caused bythis phenomenon is present in all turbomachinery in various forms.

In order to address the above challenges, blades having airfoils withenhanced wake mixing structures have been proposed. The wake mixingstructures can take a variety of forms such as crenulated or serratedtrailing edges on the airfoils. These structures, however, are limitedin their applicability because they must be formed or machined into theairfoil surface, which is a difficult and expensive process.

In addition to wake mixing, combustion or gas turbine engines(hereinafter “gas turbines”) include blades that must be activelycooled. In particular, gas turbines include a compressor, a combustor,and a turbine. As is well known in the art, in gas turbines, aircompressed in the compressor is mixed with fuel and ignited in thecombustor and then expanded through the turbine to produce power. Thecomponents within the turbine, particularly the circumferentiallyarrayed rotor and stator blades, are subjected to a hostile environmentcharacterized by the extremely high temperatures and pressures of thecombustion products that are expended therethrough. In order towithstand the repetitive thermal cycling as well as the extremetemperatures and mechanical stresses of this environment, the airfoilsmust have a robust structure and be actively cooled.

As will be appreciated, turbine rotor and stator blades often containinternal passages or circuits that form a cooling system through which acoolant, typically air bled from the compressor, is circulated. Suchcooling circuits are typically formed by internal ribs that provide therequired structural support for the airfoil, and include multiple flowpath arrangements to maintain the airfoil within an acceptabletemperature profile. The air passing through these cooling circuitsoften is vented through film cooling apertures formed on the leadingedge, trailing edge, suction side, and/or pressure side of the airfoil.

It will be appreciated that the efficiency of gas turbines increases asfiring temperatures rise. Because of this, there is a constant demandfor technological advances that enable blades to withstand ever highertemperatures. These advances sometimes include new materials that arecapable of withstanding the higher temperatures, but just as often theyinvolve improving the internal configuration of the airfoil to enhancethe blade's structure and cooling capabilities. However, because the useof coolant decreases the efficiency of the engine, new arrangements thatrely too heavily on increased levels of coolant usage merely trade oneinefficiency for another. As a result, there continues to be demand fornew airfoil arrangements that offer internal airfoil configurations andcoolant circulation that improves coolant efficiency.

A consideration that further complicates arrangement of internallycooled airfoils is the temperature differential that develops duringoperation between the airfoil's internal and external structure. Thatis, because they are exposed to the hot gas path, the external walls ofthe airfoil typically reside at much higher temperatures duringoperation than many of the internal ribs, which, for example, may havecoolant flowing through passages defined to each side of them. In fact,a common airfoil configuration includes a “four-wall” arrangement inwhich lengthy inner ribs run parallel to the pressure and suction sideouter walls. It is known that high cooling efficiency can be achieved bythe near-wall flow passages that are formed in the four-wallarrangement. A challenge with the near-wall flow passages is that theouter walls experience a significantly greater level of thermalexpansion than the inner walls. Various rib configurations have beendevised to address these challenges.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides a blade including: an airfoilbody defined by a concave pressure side outer wall and a convex suctionside outer wall that connect along leading and trailing edges and,therebetween, form a radially extending chamber for receiving the flowof a coolant, the airfoil body having an outer surface and an innersurface facing the radially extending chamber; a first corrugatedsurface on at least a portion of the outer surface of the airfoil body;a first rib partitioning the radially extending chamber, the first ribincluding a first side and an opposing second side; and a secondcorrugated surface on at least a portion of at least one of the firstand second sides of the first rib.

A second aspect of the disclosure provides a blade including: an airfoilbody defined by a concave pressure side outer wall and a convex suctionside outer wall that connect along leading and trailing edges and,therebetween, form a radially extending chamber for receiving the flowof a coolant, the airfoil body having an outer surface and an innersurface facing the radially extending chamber; a first corrugatedsurface on at least a portion of the outer surface of the airfoil body;a first rib partitioning the radially extending chamber into a firstpassage on a first side of the first rib facing one of the concavepressure side outer wall and the convex suction side outer wall, and anadjacent second passage on an opposing, second side of the first rib; asecond corrugated surface is on at least a portion of the second side ofthe first rib; and at least one of: a third corrugated surface on theinner surface of the airfoil body, the third corrugated surfaceparalleling the first corrugated surface, and a fourth corrugatedsurface on the first side of the first rib, the fourth corrugatedsurface paralleling the third corrugated surface.

A third aspect of the disclosure provides a non-transitory computerreadable storage medium storing code representative of a blade, theblade physically generated upon execution of the code by a computerizedadditive manufacturing system, the code including: code representing theblade, the blade including: an airfoil body defined by a concavepressure side outer wall and a convex suction side outer wall thatconnect along leading and trailing edges and, therebetween, form aradially extending chamber for receiving the flow of a coolant, theairfoil body having an outer surface and an inner surface facing theradially extending chamber; a first corrugated surface on a firstportion of the outer surface of the airfoil body; a first ribpartitioning the radially extending chamber, the first rib including afirst side and an opposing second side; and a second corrugated surfaceon at least a portion of at least one of the first and second sides ofthe first rib.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a schematic view of conventional aerodynamic flow within aturbomachine.

FIG. 2 shows a schematic view of an illustrative turbomachine in theform of a gas turbine system.

FIG. 3 shows a cross-sectional view of an illustrative gas turbineassembly with a three stage nozzle that may be used with the gas turbinesystem in FIG. 2.

FIG. 4 shows a perspective view of a turbine rotor blade of the type inwhich embodiments of the present disclosure may be employed.

FIG. 5 shows a cross-sectional view of a turbine rotor blade having aninner wall or rib configuration according to conventional arrangement.

FIG. 6 shows a cross-sectional view of a turbine rotor blade having anwavy profile inner wall configuration according to conventionalarrangement.

FIGS. 7 and 8 show a partially cross-sectioned, perspective view of ablade according to embodiments of the disclosure.

FIGS. 9-11 show cross-sectional views of various forms of a ribaccording to an embodiment of the disclosure.

FIGS. 12-16 show cross-sectional views of various forms of a ribaccording to another embodiment of the disclosure.

FIG. 17 shows a schematic view of an aerodynamic flow within aturbomachine using a blade according to embodiments of the disclosure.

FIG. 18 shows a schematic view of an additive manufacturing processincluding a non-transitory computer readable storage medium storing coderepresentative of a blade according to embodiments of the disclosure.

It is noted that the drawings of the disclosure are not to scale. Thedrawings are intended to depict only typical aspects of the disclosure,and therefore should not be considered as limiting the scope of thedisclosure. In the drawings, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As an initial matter, in order to clearly describe the currentdisclosure it will become necessary to select certain terminology whenreferring to and describing relevant machine components within a gasturbine. When doing this, if possible, common industry terminology willbe used and employed in a manner consistent with its accepted meaning.Unless otherwise stated, such terminology should be given a broadinterpretation consistent with the context of the present applicationand the scope of the appended claims. Those of ordinary skill in the artwill appreciate that often a particular component may be referred tousing several different or overlapping terms. What may be describedherein as being a single part may include and be referenced in anothercontext as consisting of multiple components. Alternatively, what may bedescribed herein as including multiple components may be referred toelsewhere as a single part.

In addition, several descriptive terms may be used regularly herein, andit should prove helpful to define these terms at the onset of thissection. These terms and their definitions, unless stated otherwise, areas follows. As used herein, “downstream” and “upstream” are terms thatindicate a direction relative to the flow of a fluid, such as theworking fluid through the turbomachine or, for example, the flow of airthrough the combustor or coolant through one of the turbine's componentsystems. The term “downstream” corresponds to the direction of flow ofthe fluid, and the term “upstream” refers to the direction opposite tothe flow. The terms “forward” and “aft,” without any furtherspecificity, refer to directions, with “forward” referring to the frontor compressor end of the engine, and “aft” referring to the rearward orturbine end of the engine. It is often required to describe parts thatare at differing radial positions with regard to a center axis. The term“radial” refers to movement or position perpendicular to an axis. Incases such as this, if a first component resides closer to the axis thana second component, it will be stated herein that the first component is“radially inward” or “inboard” of the second component. If, on the otherhand, the first component resides further from the axis than the secondcomponent, it may be stated herein that the first component is “radiallyoutward” or “outboard” of the second component. The term “axial” refersto movement or position parallel to an axis. Finally, the term“circumferential” refers to movement or position around an axis. It willbe appreciated that such terms may be applied in relation to the centeraxis of the turbomachine.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about,” “approximately” and “substantially,” are notto be limited to the precise value specified. In at least someinstances, the approximating language may correspond to the precision ofan instrument for measuring the value. Here and throughout thespecification and claims, range limitations may be combined and/orinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise.“Approximately” as applied to a particular value of a range applies toboth values, and unless otherwise dependent on the precision of theinstrument measuring the value, may indicate +/−10% of the statedvalue(s).

FIG. 2 shows a schematic illustration of an illustrative turbomachine100 in the form of a combustion or gas turbine system. Turbomachine 100includes a compressor 102 and a combustor 104. Combustor 104 includes acombustion region 105 and a fuel nozzle assembly 106. Turbomachine 100also includes a turbine 108 and a common compressor/turbine shaft 110(sometimes referred to as rotor 110). In one embodiment, the combustionturbine system is a MS7001FB engine, sometimes referred to as a 9FBengine, commercially available from General Electric Company,Greenville, S.C. The present disclosure is not limited to any oneparticular combustion turbine system and may be implanted in connectionwith other engines including, for example, the MS7001FA (7FA), theMS9001FA (9FA), the 7HA and the 9HA engine models of General ElectricCompany. Furthermore, the present disclosure is not limited to anyparticular turbomachine, and may be applicable to, for example, steamturbines, jet engines, compressors, turbofans, etc.

In operation, air flows through compressor 102 and compressed air issupplied to combustor 104. Specifically, the compressed air is suppliedto fuel nozzle assembly 106 that is integral to combustor 104. Assembly106 is in flow communication with combustion region 105. Fuel nozzleassembly 106 is also in flow communication with a fuel source (not shownin FIG. 2) and channels fuel and air to combustion region 105. Combustor104 ignites and combusts fuel. Combustor 104 is in flow communicationwith turbine 108 for which gas stream thermal energy is converted tomechanical rotational energy. Turbine 108 is rotatably coupled to anddrives rotor 110. Compressor 102 also is rotatably coupled to rotor 110.In the illustrative embodiment, there is a plurality of combustors 104and fuel nozzle assemblies 106.

FIG. 3 shows a cross-sectional view of an illustrative turbine assembly108 of turbomachine 100 (FIG. 2) with a three stage nozzle that may beused with the gas turbine system in FIG. 2. Turbine assembly 108includes a row of blades 109 coupled to a stationary casing ofturbomachine 100 and axially adjacent another row of blades 113. Here,row of blades 109 includes stationary blades or vanes 112. A vane 112may be held in turbine assembly 108 by a radially outer platform 114 anda radially inner platform 116. Row of blades 113 in turbine assembly 108includes rotating blades 120 coupled to rotor 110 and rotating with therotor. Rotating blades 120 may include a radially inward platform 122(at root of blade) coupled to rotor 110 and a radially outward tip 124(at tip of blade). As used herein, the term “blade” shall refercollectively to stationary vanes or blades 112 and rotating blades 120,unless otherwise stated.

FIG. 4 is a perspective view of a turbine rotor blade 130 of the type inwhich embodiments of the present disclosure may be employed. Turbinerotor blade 130 includes a root 132 by which rotor blade 130 attaches torotor 110 (FIG. 3). Root 132 may include a dovetail configured formounting in a corresponding dovetail slot in the perimeter of the rotordisc. Root 132 may further include a shank that extends between thedovetail and a platform 134, which is disposed at the junction ofairfoil 136 and root 132 and defines a portion of the inboard boundaryof the flow path through turbine 100. It will be appreciated thatairfoil 136 is the active component of rotor blade 130 that interceptsthe flow of working fluid and induces the rotor disc to rotate. Whilethe blade of this example is a turbine rotor blade 130, it will beappreciated that the present disclosure also may be applied to othertypes of blades within turbine engine 100, including turbine statorblades 112 (FIG. 3) (vanes). It will be seen that airfoil 136 of rotorblade 130 includes a concave pressure side (PS) outer wall 140 and acircumferentially or laterally opposite convex suction side (SS) outerwall 142 extending axially between opposite leading and trailing edges144, 146 respectively. Sidewalls 140 and 142 also extend in the radialdirection from platform 134 to an outboard tip 148. (It will beappreciated that the application of the present disclosure may not belimited to turbine rotor blades, but may also be applicable to statorblades (vanes). The usage of rotor blades in the several embodimentsdescribed herein is merely illustrative unless otherwise stated.)

FIGS. 5 and 6 show cross-sectional views of two example internal wallconstructions as may be found in a rotor blade airfoil 136 having aconventional arrangement. As indicated, an outer surface of airfoil 136may be defined by a relatively thin pressure side (PS) outer wall 140and suction side (SS) outer wall 142, which may be connected via aplurality of radially extending and intersecting ribs 150. Ribs 150 areconfigured to provide structural support to airfoil 136, while alsodefining a plurality of radially extending and substantially separatedflow passages 152. Typically, ribs 150 extend radially so to partitionflow passages 152 over much of the radial height of airfoil 136, but theflow passage may be connected along the periphery of the airfoil so todefine a cooling circuit. That is, flow passages 152 may fluidlycommunicate at the outboard or inboard edges of airfoil 136, as well asvia a number of smaller crossover passages 154 or impingement apertures(latter not shown) that may be positioned therebetween. In this mannercertain of flow passages 152 together may form a winding or serpentinecooling circuit. Additionally, film cooling ports (not shown) may beincluded that provide outlets through which coolant is released fromflow passages 152 onto an outer surface of airfoil 136.

Ribs 150 may include two different types, which then, as providedherein, may be subdivided further. A first type, a camber line rib 162,is typically a lengthy rib that extends in parallel or approximatelyparallel to the camber line of the airfoil, which is a reference linestretching from a leading edge 144 to a trailing edge 146 that connectsthe midpoints between pressure side outer wall 140 and suction sideouter wall 142. As is often the case, the illustrative conventionalconfiguration of FIGS. 5 and 6 include two camber line ribs 162, apressure side camber line rib 163, which also may be referred to as thepressure side outer wall given the manner in which it is offset from andclose to the pressure side outer wall 140, and a suction side camberline rib 164, which also may be referred to as the suction side outerwall given the manner in which it is offset from and close to thesuction side outer wall 142. As mentioned, these types of arrangementsare often referred to as having a “four-wall” configuration due to theprevalent four main walls that include two outer walls 140, 142 and twocamber line ribs 163, 164. It will be appreciated that outer walls 140,142 and camber line ribs 162 may be formed using any now known or laterdeveloped technique, e.g., via casting or additive manufacturing asintegral components.

The second type of rib is referred to herein as a transverse rib 166.Transverse ribs 166 are the shorter ribs that are shown connecting thewalls and inner ribs of the four-wall configuration. As indicated, thefour walls may be connected by a number of transverse ribs 166, whichmay be further classified according to which of the walls each connects.As used herein, transverse ribs 166 that connect pressure side outerwall 140 to pressure side camber line rib 163 are referred to aspressure side transverse ribs 167. Transverse ribs 166 that connectsuction side outer wall 142 to suction side camber line rib 164 arereferred to as suction side transverse ribs 168. Transverse ribs 166that connect pressure side camber line rib 163 to suction side camberline rib 164 are referred to as center transverse ribs 169. In general,the purpose of any internal configuration in an airfoil 136 is toprovide efficient near-wall cooling, in which the cooling air flows inchannels adjacent to outer walls 140, 142 of airfoil 136. It will beappreciated that near-wall cooling is advantageous because the coolingair is in close proximity of the hot outer surfaces of the airfoil, andthe resulting heat transfer coefficients are high due to the high flowvelocity achieved by restricting the flow through narrow channels.

As shown in one example in FIG. 6, one approach employs certain curvingor bubbled or sinusoidal or wavy internal ribs (hereinafter “wavy ribs”)that alleviate imbalanced thermal stresses that often occur in theairfoil of blades such as turbine blades. These structures reduce thestiffness of the internal structure of airfoil 136 so to providetargeted flexibility by which stress concentrations are dispersed andstrain off-loaded to other structural regions that are better able towithstand it. This may include, for example, off-loading stress to aregion that spreads the strain over a larger area, or, perhaps,structure that offloads tensile stress for a compressive load, which istypically more preferable. In this manner, life-shortening stressconcentrations and strain may be avoided.

In accordance with embodiments of the disclosure, at least portions ofouter walls 140, 142 and an internal rib 200 (FIGS. 7-15) are configuredto include corrugated surfaces to improve cooling efficiency andexternal corrugated surfaces to improve wake mixing. In one embodiment,shown in partially cross-sectional, perspective views in FIGS. 7-8, thedisclosure provides a blade 200 for turbomachine 100 (FIG. 2) includingan airfoil body 202 defined by a concave pressure side outer wall 204and a convex suction side outer wall 206. Outer walls 204, 206 connectalong a leading edge 208 and a trailing edge 210 and, therebetween, forma radially extending chamber 212 for receiving the flow of a coolant.Airfoil body 202 thus has an outer surface 220 (including outer surfacesof outer wall(s) 204, 206) and an inner surface 222 facing radiallyextending chamber 212.

In contrast to conventional blades, blade 200 includes a (first)corrugated surface 230 on at least a portion 232 of outer surface 220.“Corrugated surfaces” as used herein may take any form havingalternating ridges and grooves. In the embodiment of FIGS. 7-8, portion232 that includes corrugated surface 230 may include a number ofsections 236A, B and C. In one embodiment, section 236A of corrugatedsurface 230 extends from trailing edge 210 towards leading edge 208 onboth concave pressure side outer wall 204 and convex suction side outerwall 206. However, it may extend on only one wall 204, 206, if desired.In one embodiment, section 236A of corrugated surface 230 eventuallyfades to a smooth surface 234 just aft of leading edge 208. That is,section 236A of portion 232 of outer surface 222 of airfoil body 202extends only partially along at least one of concave pressure side outerwall 204 and convex suction side outer wall 206 from trailing edge 210towards leading edge 208. However, section 236A of portion 230 mayextend the entire length of one or both outer walls 204, 206 fromtrailing edge 210 to leading edge 208, if desired.

Portion 230 may include a second section 236B extending from leadingedge 208 partially towards trailing edge 210, and a third section 236Cradially spaced from second section 236B extending from leading edge 208partially towards trailing edge 210. In the embodiment shown, secondsection 236B and third section 236C would be adjacent inner and outerplatforms (116, 114 or 122 (FIG. 3) or tip shroud 124 (FIG. 3)), as thecase may be, but that is not necessary in all instances as they can beradially space therefrom.

In any of the FIGS. 7 and 8 embodiments, trailing edge 210 mayoptionally include a crenulated or serrated edge 240 (hereafter“crenulated trailing edge 240”) including a plurality of chevrons 242.“Chevrons” 242, as used herein, are defined as triangular serration,sinusoidal or undulating planform changes that are employed along atleast a portion of trailing edge 210. While crenulated trailing edge 240has been illustrated in the form of a serrated edge having a number ofspaced chevrons, the edge may include any form of serration, notches,projections, scallops, etc. Corrugated surface(s) 230 (portion 232 withsection(s) 236A, B and/or C) and/or crenulated trailing edge 240 act toimprove wave mixing, as will be described in greater detail herein.

As shown in a cross-sectional views in FIGS. 9-11, blade 200 may alsoinclude a (second) corrugated surface 262 on one or more internal ribs,each of which partitions radially extending chamber 212 in one way oranother.

FIGS. 9-11 shows a cross-sectional view along line A-A in FIGS. 7-8showing a rib 262 partitioning radially extending chamber 212. As shownin FIG. 9, rib 262 includes a first side 270 and an opposing second side272 with first side 270 facing outwardly towards outer wall 204 or 206.In the example of FIGS. 7-9, rib 262 may include a form of rib thatpartitions radially extending chamber 212 into a first passage 274 onfirst side 270 of rib 262 facing concave pressure side outer wall 204 orconvex suction side outer wall 206 (both in FIG. 9 because ofcross-section), and an adjacent second passage 276 on second side 272 ofrib 262. In the example shown, rib 262 may take the form of at least aportion of any camber line rib 263, 264, described herein. It isemphasized, however, rib 262 according to this embodiment may includeany internal rib that partitions radially extending chamber 212 intopassages 274, 276, e.g., any camber line rib, any transverse rib 166(FIGS. 5-6), etc. Also, it is emphasized that the teachings of thedisclosure need not be applied to both camber line ribs 263, 264 at thesame time.

As shown in FIG. 9, in accordance with embodiments of the disclosure, acorrugated surface 280 may be provided on at least a portion of at leastone of first side 270 and second sides 272 of rib 262 (both shown inFIG. 9). As used herein, “at least a portion” can include any radialamount, any axial amount or combinations thereof of a rib or surface,e.g., a portion or all, regardless of what may be shown in the drawings.In FIG. 9, corrugated surface 280 is on first side 270 of rib 262, i.e.,facing outwardly toward outer wall 204 or 206.

As shown in another embodiment in the cross-sectional view in FIG. 10,blade 200 may also optionally include a (third) corrugated surface 282on at least a portion of an inner surface 222 of airfoil body 202, i.e.,on all or part of inner surface 222 of one or more outer walls 204, 206(both in FIG. 9). Corrugated surface 282 may parallel corrugated surface230, i.e., where section(s) 236A-C of portion 232 are provided. As usedherein, relative to corrugated surfaces, “parallel” indicates the tworespective corrugated surfaces match such that wherever one corrugatedsurface exists on one surface of the rib or wall, the other corrugatesurface exists on the opposing side surface of the rib or wall tomaintain the thickness of the rib or wall along a length thereof. Somevariance in the parallelism may be possible in, for example, transitionareas between adjacent structures, transition areas where corrugatedsurfaces stop, etc. Further, the “parallelism” described herein may beunderstood to be that possible within now known or later developedadditive manufacturing or casting tolerances. In the instant example,wherever corrugated surface 230 exists on outer surface 220, corrugatesurface 282 exists on inner surface 222. Further, where corrugatedsurface 230 extends outwardly, e.g., relative to radial passage 212,corrugated surface 282 also extends outwardly, maintaining a thicknessof outer wall(s) 204, 206. In one embodiment, corrugated surface 280parallels corrugated surface 282 to maintain substantially constantspacing between opposing walls of passages 274.

FIG. 11 shows a cross-sectional view of another embodiment in whichblade 200 may also optionally include a (fourth) corrugated surface 284on second side 272 of rib 262. As illustrated, corrugated surface 284parallels corrugated surface 280. That is, wherever corrugated surface280 exists on first side 270, corrugated surface 284 exists on secondside 272. Further, where corrugated surface 280 extends outwardly, e.g.,relative to radial passage 212, corrugated surface 284 also extendsoutwardly, maintaining a thickness of rib 262. Again, some variance inthe parallelism may be possible in, for example, transition areasbetween adjacent structures.

While rib 262 has been described relative to a wavy profile ribconfiguration, as shown generally in FIGS. 6-8, the teachings of thedisclosure can be applied to any form of internal rib, e.g., straight(as in FIG. 5) or curved.

Referring to FIGS. 7 and 8 in combination with FIGS. 12 and 13, inanother embodiment, a rib 290 may partition radially extending chamber212. FIG. 12 shows a cross-sectional view along line B-B in FIGS. 7 and8 of rib 290, and FIG. 13 shows a partial perspective view of rib 290.In this embodiment, rib 290 does not form a passage on either sidethereof; rather, rib 290 extends as a fin that partitions radiallyextending chamber 212. As shown in FIGS. 12 and 13, rib 290 may includea first side 292 facing concave pressure side outer wall 204 (as shown)or convex suction side outer wall 206, and a second side 294 facingradially extending chamber 212. A pin bank 300 may be positioned onfirst side 292 between rib 290 and concave pressure side outer wall 204(as shown) or convex suction side outer wall 206. As understood in thefield, pin bank 300 may include an array of pins 302 extending betweenfirst side 292 of rib 290 and inner surface 222 of outer wall 204(shown) or 206. Coolant flows about pins 302 to assist heat transfer. Acorrugated surface 310 may be on at least a portion of second side 294of rib 290. Another corrugated surface 312 may be positioned on innersurface 222 of airfoil body 202. Corrugated surface 312 parallelscorrugated surface 230 on outer surface 220 of outer wall 204 or 206.Here, pin bank 300 couples to corrugated surface 312. FIGS. 12 and 13also show an optional corrugated surface 314 on at least a portion offirst side 292 of rib 290. Here, pin bank 300 also couples to corrugatedsurface 314. FIGS. 14 and 15 show a perspective views illustrating howonly one each of corrugated surfaces 312, 314 may be employed: nocorrugated surface 312 in FIG. 14, and no corrugated surface 314 in FIG.15. FIGS. 14 and 15 also show the option of providing a corrugatedsurface 316 on internal surface 222 of concave suction side wall 204 orconvex suction side wall 206 (shown) that does not include pin bank 300and rib 290. Corrugated surface 316 parallels corrugated surface 230 onouter surface 220 of outer wall 204 or 206 (shown). FIG. 16 showsanother embodiment which four corrugated surfaces 230, 312, 310 and 314are provided in the area in which pin bank 300 is positioned. Corrugatedsurfaces on opposing sides of a wall or a rib may parallel each other,as may corrugated surfaces that face one another. In FIG. 16, pin bank300 couples to corrugated surfaces 312 and 314. While rib 290 and pinbank 300 have been illustrated in FIGS. 12-16 as connecting to concavepressure side wall 204, it is understood that it may be applied toconvex suction side outer wall 206 in a similar fashion. In addition, itis also understood that, space within radially extending chamber 212permitting, two ribs 290 may be employed, one for each outer wall 204,206.

The rib embodiments of FIGS. 9-11 and 12-16 can be used separately,i.e., by themselves within a given blade 200, or may be used together,as shown in FIGS. 7 and 8. That is, both ribs 262 and 290 may beemployed to partition radially extending chamber 212, as describedherein. Where both are used, one rib, e.g. rib 290, may be positioned ata location distal (distanced) from the other rib, e.g., rib 262,providing for the advantages of corrugated internal ribs in differentlocations within the overall rib configuration.

With further reference to FIGS. 7 and 12, corrugated surface 230 (FIG.7) as a representative for all corrugated surfaces described herein andcrenulated trailing edge 240 (FIG. 12) is shown as having angles αrelative to horizontal. In accordance with embodiments of thedisclosure, angle α is no greater than 45°. That is, each corrugatedsurface and crenulated trailing edge 240 include surfaces extending atno greater than 45° relative to horizontal. As will be appreciated, suchangling is a current limitation of now known additive manufacturingtechniques. In other embodiments, for example, where blade 200 ismanufactured by a casting process, angle α is not limited to 45° and maybe greater than or less than 45°.

FIGS. 7-16 show corrugated surface(s) as sinusoidal with identicalrounded ridges and grooves of equal amplitude (height) and wavelength λ(labeled in FIG. 7 only) between a root (platform end 122 (FIG. 3)) anda tip (shroud end 140 (FIG. 3) of blade 200. It is emphasized thatcorrugated surfaces may take a variety of alternative forms. Forexample, corrugated surface(s) may be: sinusoidal and have roundedridges and grooves of different wavelength λ (FIG. 7 only) and/oramplitude (height from base surface); sinusoidal and have rounded ridgesand grooves of equal wavelength λ, but inconsistent amplitude (even to apoint, as shown in FIGS. 7-8, of being discontinuous between a root(platform end 122 (FIGS. 7 and 8, near leading edge 208)) and a tip(shroud end 140 (FIG. 3) of blade 200); sinusoidal and have roundedridges and grooves of equal amplitude, but inconsistent wavelengths λ;and with different shape corrugations. The amplitude, wavelength λ,layout and/or waveforms may change in any way required to attain thedesired external wake mixing and/or internal cooling. While variousembodiments of corrugated surface(s) have been described herein, it isemphasized that a large variety of alternatives are also possible andthat any can be combined in any fashion. Further, corrugated surface(s)can be varied in a number of ways including but not limited to:amplitude, wavelength, angle of approach (relative to the rotor), angleof exiting (relative to the rotor), curvature (relative to the rotor),waveform shape, length extending forward from the trailing or leadingedge, one side or both sides of the airfoil body on which provided,radial extent upon which provided (some or all, continuous ordiscontinuous), etc.

FIG. 17 shows a schematic view of an aerodynamic flow within aturbomachine using a blade 200 according to embodiments of thedisclosure. In operation, embodiments of the disclosed blade 200 act toenhance the mixing of an airfoil wake in a constant area region 310between airfoil rows 312, 314, through the introduction of discretevortex structures created by corrugated surface 230 (FIGS. 7-8) and/orcrenulated trailing edge 240 (FIGS. 7-8). The goal of corrugated surface230 and crenulated trailing edge 240 is to minimize the velocity deficitbefore the wake enters downstream blade row 314, which reduces thegeneration of mixing loss within downstream blade row 314: comparelocation 316 in FIG. 17 with location 20 in FIG. 1, and location 318 inFIG. 17 with location 22 in FIG. 1. Moving the mixing loss from withindownstream blade row 314 to constant area gap region 310 ahead ofdownstream blade row 314 thus produces a net gain in efficiency. Blade200 provides this functionality without having to reduce the strength ofthe wake (e.g., by reducing the diameter of the trailing edge), which isimpractical due to mechanical and thermal concerns. Blade 200 also doesnot require increasing the space for the wake to mix before enteringdownstream blade row 314, which may result in a higher net loss due tofriction losses associated with the longer inner and outer walls of theflowpath and creates a longer turbomachine, which increases cost andlowers power density. Blade 200 also removes the need for complex airjets to create the mixing.

In addition, corrugated surfaces on internal ribs and/or walls providesimproved cooling compared to conventional linear ribs/walls withoutadding weight. The improved cooling can lead to longer part life.

Blade 200 may include any metal or metal compound capable ofwithstanding the environment in which used. Blade 200 can be cast, oradvantageously made using additive manufacturing. In regard to thelatter manufacturing format, each surface and, in particular, corrugatedsurface(s) 230, 280, 282, 312, 314, etc., may include surfaces extendingat no greater than 45° relative to horizontal, as noted herein. That is,none of the ridges or grooves of corrugate surface(s) or edges ofcrenulated trailing edge 240 extend at greater than 45° relative tohorizontal. It is through additive manufacturing that airfoil body 202can be formed including a plurality of integral material layers.

As used herein, additive manufacturing (AM) may include any process ofproducing an object through the successive layering of material ratherthan the removal of material, which is the case with conventionalprocesses. Additive manufacturing can create complex geometries withoutthe use of any sort of tools, molds or fixtures, and with little or nowaste material. Instead of machining components from solid billets ofmetal, much of which is cut away and discarded, the only material usedin additive manufacturing is what is required to shape the part.Additive manufacturing processes may include but are not limited to: 3Dprinting, rapid prototyping (RP), direct digital manufacturing (DDM),binder jetting, selective laser melting (SLM) and direct metal lasermelting (DMLM). In the current setting, DMLM has been foundadvantageous.

To illustrate an example of an additive manufacturing process, FIG. 18shows a schematic/block view of an illustrative computerized additivemanufacturing system 900 for generating an object 902. In this example,system 900 is arranged for DMLM. It is understood that the generalteachings of the disclosure are equally applicable to other forms ofadditive manufacturing. Object 902 is illustrated as blade 200 asdescribed herein. AM system 900 generally includes a computerizedadditive manufacturing (AM) control system 904 and an AM printer 906. AMsystem 900, as will be described, executes code 920 that includes a setof computer-executable instructions defining blade 200 to physicallygenerate the object using AM printer 906. Each AM process may usedifferent raw materials in the form of, for example, fine-grain powder,liquid (e.g., polymers), sheet, etc., a stock of which may be held in achamber 910 of AM printer 906. In the instant case, blade 200 may bemade of a metal or a metal compound. As illustrated, an applicator 912may create a thin layer of raw material 914 spread out as the blankcanvas from which each successive slice of the final object will becreated. In other cases, applicator 912 may directly apply or print thenext layer onto a previous layer as defined by code 920, e.g., where thematerial is a polymer or where a metal binder jetting process is used.In the example shown, a laser or electron beam 916 fuses particles foreach slice, as defined by code 920, but this may not be necessary wherea quick setting liquid plastic/polymer is employed. Various parts of AMprinter 906 may move to accommodate the addition of each new layer,e.g., a build platform 918 may lower and/or chamber 910 and/orapplicator 912 may rise after each layer. AM control system 904 is shownimplemented on computer 930 as computer program code. To this extent,computer 930 is shown including a memory 932, a processor 934, aninput/output (I/O) interface 936, and a bus 938. Further, computer 930is shown in communication with an external I/O device/resource 940 and astorage system 942. In general, processor 934 executes computer programcode, such as AM control system 904, that is stored in memory 932 and/orstorage system 942 under instructions from code 920 representative ofblade 200, described herein. While executing computer program code,processor 934 can read and/or write data to/from memory 932, storagesystem 942, I/O device 940 and/or AM printer 906. Bus 938 provides acommunication link between each of the components in computer 930, andI/O device 940 can comprise any device that enables a user to interactwith computer 940 (e.g., keyboard, pointing device, display,touchscreen, etc.). Computer 930 is only representative of variouspossible combinations of hardware and software. For example, processor934 may comprise a single processing unit, or be distributed across oneor more processing units in one or more locations, e.g., on a client andserver. Similarly, memory 932 and/or storage system 942 may reside atone or more physical locations. Memory 932 and/or storage system 942 cancomprise any combination of various types of non-transitory computerreadable storage medium including magnetic media, optical media, randomaccess memory (RAM), read only memory (ROM), etc. Computer 930 cancomprise any type of computing device such as a network server, adesktop computer, a laptop, a handheld device, a mobile smartphone, apersonal data assistant, etc.

Additive manufacturing processes begin with a non-transitory computerreadable storage medium (e.g., memory 932, storage system 942, etc.)storing code 920 representative of blade 200. As noted, code 920includes a set of computer-executable instructions defining blade 200that can be used to physically generate, among other things, corrugatedsurface(s), upon execution of the code by system 900. For example, code920 may include a precisely defined 3D model of blade 200 and can begenerated from any of a large variety of well known computer aideddesign (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3DMax, etc. In this regard, code 920 can take any now known or laterdeveloped file format. For example, code 920 may be in the StandardTessellation Language (STL) which was created for stereolithography CADprograms of 3D Systems, or an additive manufacturing file (AMF), whichis an American Society of Mechanical Engineers (ASME) standard that isan extensible markup-language (XML) based format designed to allow anyCAD software to describe the shape and composition of anythree-dimensional object to be fabricated on any AM printer. Code 920may be translated between different formats, converted into a set ofdata signals and transmitted, received as a set of data signals andconverted to code, stored, etc., as necessary. Code 920 may be an inputto system 900 and may come from a part designer, an intellectualproperty (IP) provider, a design company, the operator or owner ofsystem 900, or from other sources. In any event, AM control system 904executes code 920, dividing blade 200 into a series of thin slices thatit assembles using AM printer 906 in successive layers of liquid,powder, sheet or other material. In the DMLM example, each layer ismelted to the exact geometry defined by code 920 and fused to thepreceding layer. Subsequently, blade 200 may be exposed to any varietyof finishing processes, e.g., minor machining, sealing, polishing,assembly to other part of the blade, etc.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A blade comprising: an airfoil body defined by aconcave pressure side outer wall and a convex suction side outer wallthat connect along leading and trailing edges and, therebetween, form aradially extending chamber for receiving the flow of a coolant, theairfoil body having an outer surface and an inner surface facing theradially extending chamber; a first corrugated surface on at least aportion of the outer surface of the airfoil body; a first ribpartitioning the radially extending chamber, the first rib including afirst side and an opposing second side; and a second corrugated surfaceon at least a portion of at least one of the first and second sides ofthe first rib.
 2. The blade of claim 1, further comprising a pin bankpositioned on the first side of the first rib between the first rib andone of the concave pressure side outer wall and the convex suction sideouter wall.
 3. The blade of claim 2, wherein the second corrugatedsurface is on at least a portion of the second side of the first rib. 4.The blade of claim 3, further comprising at least one of: a thirdcorrugated surface on the inner surface of the airfoil body, wherein thethird corrugated surface parallels the first corrugated surface and thepin bank couples to the third corrugated surface; and a fourthcorrugated surface on at least a portion of the first side of the firstrib, wherein the pin bank couples to the fourth corrugated surface. 5.The blade of claim 1, wherein the first rib partitions the radiallyextending chamber into a first passage on the first side of the firstrib facing one of the concave pressure side outer wall and the convexsuction side outer wall, and an adjacent second passage on the secondside of the first rib.
 6. The blade of claim 5, wherein the first ribincludes at least a portion of a camber line rib.
 7. The blade of claim5, wherein the second corrugated surface is on at least a portion of thefirst side of the first rib.
 8. The blade of claim 7, further comprisingat least one of: a third corrugated surface on the inner surface of theairfoil body, the third corrugated surface paralleling the firstcorrugated surface; and a fourth corrugated surface on the second sideof the first rib, the fourth corrugated surface paralleling the secondcorrugated surface.
 9. The blade of claim 8, further comprising: asecond rib partitioning the radially extending chamber at a locationdistal from the first rib, the second rib including a first side and anopposing second side, and a pin bank positioned on the first side of thesecond rib between the first side and one of the concave pressure sideouter wall and the convex suction side outer wall.
 10. The blade ofclaim 9, further comprising at least one of: a fifth corrugated surfaceis on at least a portion of the second side of the second rib; a sixthcorrugated surface on the inner surface of the airfoil body, wherein thesixth corrugated surface parallels the first corrugated surface and thepin bank couples to the sixth corrugated surface; and a seventhcorrugated surface on at least a portion of the first side of the secondrib, wherein the pin bank couples to the seventh corrugated surface. 11.The blade of claim 1, wherein the portion of the outer surface of theairfoil body extends only partially along at least one of the concavepressure side outer wall and the convex suction side outer wall from thetrailing edge towards the leading edge.
 12. The blade of claim 1,wherein each corrugated surface includes surfaces extending at nogreater than 45° relative to horizontal.
 13. A blade comprising: anairfoil body defined by a concave pressure side outer wall and a convexsuction side outer wall that connect along leading and trailing edgesand, therebetween, form a radially extending chamber for receiving theflow of a coolant, the airfoil body having an outer surface and an innersurface facing the radially extending chamber; a first corrugatedsurface on at least a portion of the outer surface of the airfoil body;a first rib partitioning the radially extending chamber into a firstpassage on a first side of the first rib facing one of the concavepressure side outer wall and the convex suction side outer wall, and anadjacent second passage on an opposing, second side of the first rib; asecond corrugated surface on at least a portion of the second side ofthe first rib; and at least one of: a third corrugated surface on theinner surface of the airfoil body, the third corrugated surfaceparalleling the first corrugated surface, and a fourth corrugatedsurface on the first side of the first rib, the fourth corrugatedsurface paralleling the third corrugated surface.
 14. The blade of claim13, further comprising: a second rib partitioning the radially extendingchamber at a location distal form the first rib, the second ribincluding a first side and an opposing second side, and a pin bankpositioned on the first side of the second rib between the first sideand one of the concave pressure side outer wall and the convex suctionside outer wall.
 15. The blade of claim 14, further comprising at leastone of: a fifth corrugated surface on at least a portion of the secondside of the second rib; a sixth corrugated surface on the inner surfaceof the airfoil body, wherein the sixth corrugated surface parallels thefirst corrugated surface and the pin bank couples to the sixthcorrugated surface; and a seventh corrugated surface on at least aportion of the second side of the second rib, wherein the pin bankcouples to the seventh corrugated surface.
 16. A non-transitory computerreadable storage medium storing code representative of a blade, theblade physically generated upon execution of the code by a computerizedadditive manufacturing system, the code comprising: code representingthe blade, the blade including: an airfoil body defined by a concavepressure side outer wall and a convex suction side outer wall thatconnect along leading and trailing edges and, therebetween, form aradially extending chamber for receiving the flow of a coolant, theairfoil body having an outer surface and an inner surface facing theradially extending chamber; a first corrugated surface on a firstportion of the outer surface of the airfoil body; a first ribpartitioning the radially extending chamber, the first rib including afirst side and an opposing second side; and a second corrugated surfaceon at least a portion of at least one of the first and second sides ofthe first rib.
 17. The non-transitory computer readable storage mediumof claim 16, wherein the second corrugated surface is on at least aportion of the second side of the first rib, and wherein the codefurther comprises at least one of: a third corrugated surface on theinner surface of the airfoil body, wherein the third corrugated surfaceparallels the first corrugated surface and a pin bank couples to thethird corrugated surface, and a fourth corrugated surface on at least aportion of the first side of the first rib, wherein the pin bank couplesto the fourth corrugated surface on the at least the portion of thefirst side of the rib.
 18. The non-transitory computer readable storagemedium of claim 16, wherein the first rib partitions the radiallyextending chamber into a first passage on the first side of the firstrib facing at least one of the concave pressure side outer wall and theconvex suction side outer wall, and an adjacent second passage on thesecond side of the first rib, and wherein the second corrugated surfaceis on at least a portion of the second side of the first rib; andwherein the code further comprises at least one of a third corrugatedsurface on the inner surface of the airfoil body, the third corrugatedsurface paralleling the first corrugated surface, and a fourthcorrugated surface on the first side of the first rib, the fourthcorrugated surface paralleling the second corrugated surface.
 19. Thenon-transitory computer readable storage medium of claim 18, wherein thecode further comprises: a second rib partitioning the radially extendingchamber, the second rib including a first side and an opposing secondside; a pin bank positioned on the first side of the second rib betweenthe first side and one of the concave pressure side outer wall and theconvex suction side outer wall; and at least one of: a fifth corrugatedsurface is on at least a portion of the second side of the second rib; asixth corrugated surface on the inner surface of the airfoil body,wherein the sixth corrugated surface parallels the first corrugatedsurface and the pin bank couples to the sixth corrugated surface; aseventh corrugated surface on at least a portion of the first side ofthe second rib, wherein the pin bank couples to the seventh corrugatedsurface.
 20. The non-transitory computer readable storage medium ofclaim 1, wherein each corrugated surface includes surfaces extending atno greater than 45° relative to horizontal.